// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "content/browser/renderer_host/input/synthetic_gesture_target_base.h"

#include "content/browser/renderer_host/render_widget_host_impl.h"
#include "content/browser/renderer_host/render_widget_host_view_base.h"
#include "content/browser/renderer_host/ui_events_helper.h"
#include "content/common/input_messages.h"
#include "third_party/WebKit/public/platform/WebInputEvent.h"
#include "ui/events/blink/web_input_event_traits.h"
#include "ui/events/event.h"
#include "ui/events/latency_info.h"

using blink::WebInputEvent;
using blink::WebMouseEvent;
using blink::WebMouseWheelEvent;
using blink::WebTouchEvent;
using blink::WebTouchPoint;

namespace content {
namespace {

    // This value was determined experimentally. It was sufficient to not cause a
    // fling on Android and Aura.
    const int kPointerAssumedStoppedTimeMs = 100;

    // SyntheticGestureTargetBase passes input events straight on to the renderer
    // without going through a gesture recognition framework. There is thus no touch
    // slop.
    const float kTouchSlopInDips = 0.0f;

} // namespace

SyntheticGestureTargetBase::SyntheticGestureTargetBase(
    RenderWidgetHostImpl* host)
    : host_(host)
{
    DCHECK(host);
}

SyntheticGestureTargetBase::~SyntheticGestureTargetBase()
{
}

void SyntheticGestureTargetBase::DispatchInputEventToPlatform(
    const WebInputEvent& event)
{
    TRACE_EVENT1("input", "SyntheticGestureTarget::DispatchInputEventToPlatform",
        "type", WebInputEvent::GetName(event.type()));

    ui::LatencyInfo latency_info;
    latency_info.AddLatencyNumber(ui::INPUT_EVENT_LATENCY_UI_COMPONENT, 0, 0);

    if (WebInputEvent::isTouchEventType(event.type())) {
        const WebTouchEvent& web_touch = static_cast<const WebTouchEvent&>(event);

        // Check that all touch pointers are within the content bounds.
        for (unsigned i = 0; i < web_touch.touchesLength; i++)
            CHECK(web_touch.touches[i].state != WebTouchPoint::StatePressed || PointIsWithinContents(web_touch.touches[i].position.x, web_touch.touches[i].position.y))
                << "Touch coordinates are not within content bounds on TouchStart.";

        DispatchWebTouchEventToPlatform(web_touch, latency_info);
    } else if (event.type() == WebInputEvent::MouseWheel) {
        const WebMouseWheelEvent& web_wheel = static_cast<const WebMouseWheelEvent&>(event);
        CHECK(PointIsWithinContents(web_wheel.x, web_wheel.y))
            << "Mouse wheel position is not within content bounds.";
        DispatchWebMouseWheelEventToPlatform(web_wheel, latency_info);
    } else if (WebInputEvent::isMouseEventType(event.type())) {
        const WebMouseEvent& web_mouse = static_cast<const WebMouseEvent&>(event);
        CHECK(event.type() != WebInputEvent::MouseDown || PointIsWithinContents(web_mouse.x, web_mouse.y))
            << "Mouse pointer is not within content bounds on MouseDown.";
        DispatchWebMouseEventToPlatform(web_mouse, latency_info);
    } else {
        NOTREACHED();
    }
}

void SyntheticGestureTargetBase::DispatchWebTouchEventToPlatform(
    const blink::WebTouchEvent& web_touch,
    const ui::LatencyInfo& latency_info)
{
    // We assume that platforms supporting touch have their own implementation of
    // SyntheticGestureTarget to route the events through their respective input
    // stack.
    CHECK(false) << "Touch events not supported for this browser.";
}

void SyntheticGestureTargetBase::DispatchWebMouseWheelEventToPlatform(
    const blink::WebMouseWheelEvent& web_wheel,
    const ui::LatencyInfo& latency_info)
{
    host_->ForwardWheelEventWithLatencyInfo(web_wheel, latency_info);
}

void SyntheticGestureTargetBase::DispatchWebMouseEventToPlatform(
    const blink::WebMouseEvent& web_mouse,
    const ui::LatencyInfo& latency_info)
{
    host_->ForwardMouseEventWithLatencyInfo(web_mouse, latency_info);
}

void SyntheticGestureTargetBase::SetNeedsFlush()
{
    host_->SetNeedsFlush();
}

SyntheticGestureParams::GestureSourceType
SyntheticGestureTargetBase::GetDefaultSyntheticGestureSourceType() const
{
    return SyntheticGestureParams::MOUSE_INPUT;
}

base::TimeDelta SyntheticGestureTargetBase::PointerAssumedStoppedTime()
    const
{
    return base::TimeDelta::FromMilliseconds(kPointerAssumedStoppedTimeMs);
}

float SyntheticGestureTargetBase::GetTouchSlopInDips() const
{
    return kTouchSlopInDips;
}

float SyntheticGestureTargetBase::GetMinScalingSpanInDips() const
{
    // The minimum scaling distance is only relevant for touch gestures and the
    // base target doesn't support touch.
    NOTREACHED();
    return 0.0f;
}

bool SyntheticGestureTargetBase::PointIsWithinContents(int x, int y) const
{
    gfx::Rect bounds = host_->GetView()->GetViewBounds();
    bounds -= bounds.OffsetFromOrigin(); // Translate the bounds to (0,0).
    return bounds.Contains(x, y);
}

} // namespace content
